Memory CycleMain memory is a read/write memory that allowsdata to be retrieved (read) and stored (written) in whatis known as the memory cycle. The memory cycleincludes reading the data out of memory and/or writingthe data into memory, either by a read/write operationor by separate read and write operations. The memorycycle is based on fixed (constant) time periods forreading and/or writing data from and into memory. Assoon as read and/or write operations are initiated,almost simultaneously, address translation occurs,then the read and/or write cycle or cycles begin.MEMORY ADDRESS TRANSLATION. Oneof the most important processes that must occur beforea read or write cycle begins is the memory addresstranslation. Look at memory as a sequence of memorylocations starting at address 0 and extending to themaximum memory address available to the requester(CPU or IO(C)). Receiving or sending mail uses asimilar concept. Before mail can be received or sent,there must bean address on the envelope. Memory usesthe same principle.Memory logic identifies thememory address where a memory word is to be readfrom or written into in memory. A memory addresscan be anyone of the entire range of memory addresses(0 to maximum). To identify the desired memoryaddress, the memory logic uses a register designated asthe address register and/or translators or decoders. Thememory logic receives the logical address from theCPU or I/O and temporarily stores it in the addressregister, and then converts it to a physical address thatcan be read from or written into.Memory Address Register and/or Translator(Decoder). The address register and/or translatoridentifies the exact location from which to read the bitsor write them. The contents of the address register ortranslator identifies the memory address. The memorylogic is designed to make its selection based on the typeof memory it uses.It can be designed to identify amemory address of a single memory pcb or it can bedesigned to identify an address located in one of four ormore memory modules.Memory Address Word. As stated in thearchitecture of memory, the word contained in thememory address can be one or more bits, mostcomputers have words with at least 8 bits and some upto 128 bits in length. Variations of reading and/orwriting from and to memory can include the upper orlower half of the word, or any other variation within thedesign of a given computer. Variations are based on theinstruction types and the program. Also, if a computeris identified as an 8-bit computer and a 16-bit word isrequired for a read or write operation, then twoconsecutive memory addresses would have to be usedto complete the operation. There are many othervariations; the instruction repertoire set of yourcomputer and the technical manual will provide detailsof your computers memory operations and limitations.Here are two examples of memory addresstranslation. For the first example, use figure 6-6 as areference; it shows a 4-bit memory address. Thememory address register or translator contains 168 asfollows:Figure 6-6.4-bit address.6-6